1. Field of the Invention
The present invention relates to ink jet printers, and, more particularly, to removing excess aerosol in ink jet printers.
2. Description of the Related Art
An ink jet printer typically includes an ink jet cartridge assembly with a printhead mounted under a body. The body includes one or more ink reservoirs which are in fluid communication with the printhead. The printhead includes a plurality of heaters, which are respectively positioned in association with nozzles in a nozzle plate. The heaters are selectively actuated during printing to jet ink droplets from the corresponding nozzles in the nozzle plate.
Expelling ink through the printhead, during maintenance and printing, releases aerosol. Movement of the printhead causes uncaptured aerosol to swirl within the printer and external to the printer, allowing the aerosol to reach and ultimately rest upon numerous internal and external component parts of the printer and the work area. This contamination is undesirable as it can lead to failure of certain mechanical and electrical components. Uncontrolled release of aerosol is an increasing concern, due in large part to the current trend of decreasing droplet size, since smaller droplets have a greater tendency to stay airborne.
Capture of aerosol is not a new concept in itself. One ink jet printing apparatus includes a carriage moveable within a printer section. Exhaust pipes are positioned on opposite sides of the carriage, relative to the scan directions. A fan draws aerosol droplets from each of the exhaust pipes and through a filter.
Another ink jet printing system includes an ink jet nozzle plate, which jets ink droplets through an elongated slot onto a print medium carried by a drum. A vacuum is applied to a transverse opening positioned above the ink-jetting zone for removing aerosol ink droplets.
A mist reduction system for ink jet printers has a nozzle unit jetting an ink stream at selected ink dot placement locations onto the print medium, which is carried by a drum. A suction pump removes ink mist condensing on a deflection electrode and control electrode and also removes deflected ink from a gutter.
An ink jet recorder includes a recording head, which is moveable in transverse directions relative to a print medium. The recording head includes a pair of air stream ducts positioned on either side of an orifice plate defining a side shooter design with respect to a print medium. A dual fan assembly includes fan blades, which are respectively positioned within the corresponding air ducts. The fan blades are driven, using a rack and pinion arrangement, as the recording head is moved in scan directions relative to the stationary rack. Air is drawn in through air inlet openings and is discharged through air outlet openings associated with each respective fan blade.
Common to each of these systems is the use of active fans or suction pumps with a filter to remove the aerosol. Additional components are generally undesirable, adding to the cost, potential for breakdown, and increased effort in installing and maintaining the system.
What is needed in the art is a manner for controlling ink jet aerosol during maintenance and printing, without the use of an additional fan, to displace harmful aerosols to a filter.
The present invention relates to an ink jet aerosol control assembly and method using carrier movement as a piston pump for removing aerosols within a printer.
Carrier motion produces airflow required to sweep away the aerosols when the carrier moves from a spitting to a printing position. As the carrier moves from a spit position towards the page, and while the aerosols are still suspended, a high-pressure zone is created in front of the carrier and a low-pressure zone is created behind the carrier. This pressure difference creates airflow from the high-pressure zone to the low-pressure zone. A preferred airflow path, as well as leak paths surrounding the carrier, provides a conduit for airflow to occur. The carrier and geometry surrounding the carrier act as a piston and cylinder to create the pressure difference. The preferred airflow path is most effective while the carrier is over the spit zone. Once exposed, the preferred airflow path is no longer in the flow path between the high-pressure zone and the low-pressure zone. Airflow of sufficient velocity should therefore be provided to collect the aerosols on the filter prior to breaking flow. The manifold area may be created as large as possible to increase the pressure difference between the air inlet (spit zone) and air outlet (manifold).
In another embodiment the carrier is a piston to pump aerosols through a filter associated with an airflow path created at least in part by openings in a printer frame adjacent the carrier. As the carrier moves through the frame, during the printing process, a high-pressure zone is created in front of the carrier, according to its direction of movement and a low-pressure zone is created behind the carrier. Apertures defined in the frame allow air to pass from the high-pressure zone to the low-pressure zone. The air may be filtered in or adjacent the frame to remove airborne aerosol.
An advantage of the present invention is that it is more efficient, channeling airflows that before now had not been used within printing systems and had even been considered detrimental thereto.
Another advantage of the present invention is that the design is simple, replacing expensive components with existing components and wall structures.
A further advantage is that such system eliminates the need for certain components that are subject to wear and breakdown without inducing additional wear on the remaining components.
Yet another advantage is that airflow may be effected without the use of a fan to filter aerosols within the printer.